NOTE: These weight data are based on nonstop bidirectional air trade by U.S. and foreign carriers between the United States and other countries. The data differ from U.S. Census Bureau weight data for international air freight.

1 FedEx relocated its primary hub to Memphis in 1991.

2 United Parcel Service started all-cargo services at Louisville hub in 1981 and expanded the services in 1998.

3 FedEx opens major hub in Indianapolis in 1988.

SOURCE: U.S. Department of Transportation, Bureau of Transportation Statistics, Office of Airline Information data, June 2009.